The strategic goal of this research is to improve scientific understanding of coral reef ecosystems throughout the Pacific, and serve as the basis for improved conservation and resource management. The recent designation of the Pacific Remote Islands Marine National Monument highlights the importance of this research.

With their extremely isolated location, many of the Pacific Remote Island Areas host a vibrate marine ecosystem.Previous Pacific RAMP cruises have documented relatively high coral cover and diversity; and high densities of large-bodied reef fish including large numbers of apex predators such as Grey Reef Sharks (Carcharhinus amblyrhynchos) and Scalloped Hammerhead sharks (Sphyraena lewini). Many of these apex predators are rare near human population centers. AS in previous years, this Pacific RAMP cruise will perform a suite of standardized multi-disciplinary methods which include Rapid Ecological Assessments (REA) for fish, corals, other large invertebrates, and algae; towed-diver surveys for large-bodied fish and habitat composition; and oceanographic studies, which include the measurement of conductivity, temperature, and density of the water column (CTD casts); water sampling; and deployment of sea-surface temperature (SST), subsurface temperature recorders (STR) and acoustic doppler current profilers (ADCP).Scientists will also be deploying Ecological Acoustic Recorders (EARs) to learn about changes in the presence and activity of marine mammals, fish, crustaceans and other sound-producing marine life when researchers aren't there to record it otherwise. Autonomous reef monitoring structures (ARMS) will also be deployed as part of the CReefs project. ARMS are simple, standardized collecting structures designed to roughly mimic the structural complexity of reef habitats.They allow for the identification of small, hard-to-sample, but ecologically important cryptic invertebrates. ARMS are being utilized throughout the Pacific and globally to systematically assess spatial patterns and temporal changes ofbiodiversity.Use of the EARS and ARMS are an exciting addition to RAMP data collection efforts.

Follow along below to learn more about where we are going, what we are seeing, and what we have found ...

Monday, April 19, 2010

Autonomous Reef Monitoring Structure (ARMS): Recovery and Processing

By Molly Timmers and Russell Reardon

‘Reef Biodiversity: an Introduction’ posted on the 4th of February introduced coral reef diversity and the Autonomous Reef Monitoring Structure (ARMS). This post will explore the recovery and processing of these platforms.

ARMS awaiting removal on left, encapsulated ARMS on right

An ARMS is a tool used to assess the lesser known and cryptic reef organisms. For the past two years, sessile and motile critters have been colonizing the open and closed ARMS layers. One of our missions on this cruise has been to recover all the previously deployed ARMS for immediate shipboard and subsequent land-based processing.

We remove the ARMS from the benthos by attaching a milk crate lined with an 80 micron mesh over the center stack of plates comprising the structure. A buoyed rope is then attached to the latching straps on the crate, and the whole unit is pulled to the surface. The milk crate ensures that any recruited organisms within the ARMS will not fall out during transport. Once on the surface and in the small boat, the milk crate encapsulated ARMS is placed within seawater-filled bins and transported back to the Hi‘ialakai.

Back on the ship, the ARMS is disassembled within a tub of seawater. The milk crate is detached, and each layer (plate) is removed individually. The top and bottom of each plate is photographed to document the sessile organisms. Once photographed, a paint brush is used to lightly sweep any motile organisms off the plates and into a bucket of seawater. The plates are then placed in ethanol to preserve the DNA for future molecular processing.

An example of a plate photograph

Once every layer has been photographed, brushed, and preserved, all of the buckets of seawater used during the processing are sieved into the following bins: 5 mm, 2 mm, 500 ?m, and 100 ?m. The contents from the 2 mm, 500 ?m, and 100 ?m sieves are bulked and placed immediately into ethanol. Selected critters found within the 5 mm sieve are photographed, identified, and preserved individually while the remaining 5 mm organisms are bulked and placed in ethanol.

The final task is to scrape the sessile organisms from the all the plates. The scrapings are bulked and preserved. In this manner, we are able to remove, preserve, and store all of the sessile and motile organisms that have recruited to the ARMS.

When we return to land, the contents will be sent to our partners at the Smithsonian, the Florida Museum of Natural History, and the Hawaiian Institute for Marine Biology who will begin the molecular processing and taxonomic archiving. Genetic sequencing will provide a relative index of diversity for each of our survey sites. We will then be able to compare these indices among and between sites, islands, and regions. Ultimately, this process may allow us to detect and monitor changes in cryptic diversity in an effort to understand ecosystem shifts overtime.

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The mission of the Coral Reef Ecosystem Division is to provide sound science to enable informed and effective implementation of ecosystem-based management and conservation strategies for coral reef ecosystems of the U.S.-affiliated Pacific Islands Region.

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